| Panzhihua is a main production base for titanium dioxide industry, which is in rapid development, leading to the following results: the Ti-rich feedstock demand becomes larger and larger on the one hand, and about 200,000 tons of waste sulfuric acid, which cannot be processed, comes into being every year with the production process on the other hand, which has become the biggest block to hinder the development of the enterprises. In order to solve such problems, a new process of the preparation of Ti-rich feedstock, Ilmenite—Modified in high temperature—waste sulfuric acid discharged,based on the combination of domestic and international sulfuric acid method used to produce ilmenite, is proposed in the present paper. The method mentioned in this paper can not only solve the problem of the purification of the refractory ore,but also deal with the emissions the the metallurgical waste acid effectively,which is good to the sustainable development of the titanium industry in China.The ilmenite used in the experiment is from Panzhihuang Ruierxin Trade Group Co. Ltd. XRD and SEM are used to analyze the ilmenite,and the result demonstrates that the ore is mainly composed of FeTiO3 which has compact structure and shows trigonal system,and some impurities,such as FeO、Fe2O3、CaO、MgO、SiO2、Al2O3 and so on are also contained in such ore, and the ilmenite is preprocessed to improve the rate of acid solution just because the impurities exist in the ore like choroid and are so negative to inorganic acid that cannot be extracted by acid.The advantages and disadvantages between direct calcination of ilmenite and iron-doped calcination are compared by XRD and SEM in the experiment modifying ilmenite in high temperature, and the results show that: ilmenite,which is calcined directly,still mainly consists of FeTiO3 phase,and cracks appear only on the surface of the particle only when the temperature is over 700 and the calcination process lasts 2 hour at least;however the ilmenite ℃doped with iron contains not only FeTiO3 but also Fe1.1Ti0.9O3, Fe1.04Ti0.96O3, Fe+2TiO3, Fe2TiO4, Mg2TiO4 and other new phases, and the particle with the surface seriously corraded and loose and porous, is propitious to the waste sulfuric acid leaching.The calcined product with iron doped is selected as material for acid leaching, and a best process for calcination with iron doped,Calcination Time:2h, Temperature:800℃,and Mass Ratio between iron and ilmenite :1:5, is obtained by examining the influences of temperature,time and iron mass through the orthogonal test.The influence of acid leaching temperature, leaching time,particle size and ratio between liquid and solid on impurity elements leaching rate and TiO2 grade,is studied according to level test and orthogonal test in the waste sulfuric acid leaching modified ore experiment, and the factors,which affect the TiO2 content,are acquired:time is the main factor,and temperature and particle size are weaker,and the weakest is the ratio between liquid and solid. The optimum conditions of acid leaching process,Acid Leaching Time: 8h,Acid Leaching Temperature :140 ℃,Modified Mine Size: 80-120 mesh and Ratio between liquid and solid: 10mL:1g,are also obtained by comprehensive analysis. And in the optimal conditions, the Ti-rich feedstock with 81.09 percent of TiO2, 0.88 percent of Ca O and 0.53 percent of MgO are prepared and can be used as raw material for titanium dioxide with chloride process. |
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